Amorphization during Fracture of Thin Photovoltaic Silicon Wafers

Abstract

Nanoindentation was used to stimulate and measure materials processes which occur during the initiation and propagation of micro-crack defects in monocrystalline (100) Si wafers. Silicon amorphization occurs and is accompanied by a monotonic drop in hardness and elastic modulus as the nanoindents approach the micro-crack shank or tip. Identification and profiling of localized phase transitions were obtained in the vicinity of a micro-crack using electron back-scattered diffraction (EBSD) and Raman spectroscopy and indicate that regions of amorphous Si extend for about 10 µm at the edges and ahead of a moving crack tip.